12. Pseudomonas Aeruginosa is Present in Sink Drains of Multiple ICU Wards at a Tertiary Medical Center

Introduction: Healthcare-associated infections are a rising threat to hospitalized patients. Pseudomonas aeruginosa reservoirs in the hospital environment have been connected to patient infections in intensive care units (ICUs), including the stem cell transplant and oncology (SCTO) ICU in Barnes Jewish Hospital. Sink drains were identified as a consistent source of antimicrobial resistant organism (ARO) growth, including P. aeruginosa, from year-long repeated sampling in this ICU. It is unknown if sink drains in other ICU wards are similarly contaminated with AROs. Consequently, we collected and analyzed longitudinal sink drain swabs from SCTO ICU and surgical ICU (SICU) patient and non-patient rooms to identify Pseudomonas presence in these environments.

Methods: Once a week for three weeks, sink drains from patient rooms, housekeeping closets, and soiled utility rooms in the SCTO ICU and SICU were sampled using moistened Eswabs. These swabs were then cultured on Cetrimide agar to enrich for Pseudomonas. All growth on each Cetrimide plate was subjected to metagenomic shotgun short-read sequencing, which enables identification of the taxa present in each sink drain sample.

Results: Pseudomonas species were identified in both the SCTO ICU and SICU, with the housekeeping closets and soiled utility rooms containing Pseudomonas in all sinks across all three weeks of sampling (present in 12 of 12 samples). In the SCTO ICU, Pseudomonas was present at multiple timepoints in three rooms (present in 12 of 17 samples), while the SICU contained only one room with multiple Pseudomonas-positive timepoints (present in 8 of 16 samples). Stenotrophomonas, Serratia, and Klebsiella were also identified in all sampling locations.

Impact: Pseudomonas presence in sink drains of multiple ICU wards suggests that these sink drains represent a persistent reservoir of Pseudomonas or that these sink drains are being consistently seeded with Pseudomonas, both of which warrant further exploration into the specific strains of AROs present in each sink. The presence of AROs in the SICU and non-patient rooms emphasizes the need for hospital environmental surveillance and appropriate adaptation of infection prevention measures.

OrganizationWashington University in St. Louis

Benedict EE, Newcomer EP, Sukhum KV, Cass C, Wallace MA, Johnson C, Fine J, Sax S, Bartlet MH, Burnham CD, Kwon JH, Dantas G